I remember reading the freakonomics books years ago about how a lot of names start of posh and eventually filter down throughout the years and become very common place names. Olivia is a prime example for me i grew up in the 80s and Olivia back then was looked at as an upper class old woman's name that only "posh" people would've chosen, 30 years later it has became quite commonplace and number 1 name. Emily is another past number 1 name that springs to mind also wasn't used commonly until the 90s/00s when it hit its peak and began being used by all lower/working/upper class people.
A lot of the newer names that are being used now like Arabella, Ophelia, Isabella would've of been mega posh 20 years ago but have now made their way into the mainstream.